CN105898879B

CN105898879B - Method and apparatus for registration and data transmission using fast/zero contention resolution

Info

Publication number: CN105898879B
Application number: CN201610479903.1A
Authority: CN
Inventors: 雷默·博谢拉; 大卫·菲利普·霍尔; 萨蒂什·文科博; 史蒂文·迈克尔·汉诺夫; 沃纳·克洛泽; 雷内·福列
Original assignee: BlackBerry Ltd
Current assignee: BlackBerry Ltd
Priority date: 2010-03-12
Filing date: 2011-03-10
Publication date: 2020-06-16
Anticipated expiration: 2031-03-10
Also published as: CN102792758A; EP2996423A1; TWI432068B; EP2367392A1; CA2792735C; EP3285537B1; CA2792735A1; EP3675587B1; WO2011111013A1; EP2996423B1; CN105898879A; US20110222492A1; TW201210388A; EP3675587A1; EP2367392B1; CN102792758B; US8730886B2; EP3285537A1

Abstract

Embodiments of methods and apparatus for access and contention resolution by devices in a wireless network are described. The device may communicate on a Random Access Channel (RACH). In some embodiments, a method of uniquely identifying the device is described. Other embodiments may be described and claimed.

Description

Method and apparatus for registration and data transmission using fast/zero contention resolution

The application is a divisional application named as a registration and data transmission method and device using fast/zero contention resolution, and is filed on 10/3/2011 in China patent application No.201180013145. X.

RELATED APPLICATIONS

The present application relates to patent applications having the designations 2558.054EP1(37466-FR-EPA), 2558.053EP1(37760-FR-EPA), 2558.056EP1(37759-FR-EPA), 2558.057EP1(37760-1-FR-EPA), 2558.058EP1(37760-2-FR-EPA), all filed concurrently with the present application.

Technical Field

Various embodiments described herein relate to apparatuses and methods related to wireless communications. Some embodiments relate to global system for mobile communications (GSM) networks including General Packet Radio Service (GPRS) and enhanced GPRS (egprs) networks. Some embodiments relate to Mobile Station (MS) access technologies. Some embodiments relate to communications and data transmission on a Random Access Channel (RACH).

Background

In a wireless environment where multiple devices may simultaneously request access to the network, there is a need for the network to resolve the contention. To minimize the risk of confusion associated with which device to respond to, a random number may currently be included by a device in its initial request.

However, there is a limited number of bits available for random number reference in the request message, so the probability of the following situation occurring is high: multiple devices use the same random number in the same RACH slot and there will be contention that should be resolved to avoid having multiple devices transmit on the same dedicated channel. Devices that lose contention resolution (i.e., find that they have transmitted on resources not intended for them) may consume a significant amount of power and cause delays in transmitting data that is not processed or forwarded by the network. Thus, there is a need for an efficient method for contention resolution in terms of time, power consumption, and signaling overhead in a wireless network.

Disclosure of Invention

According to an aspect of the present disclosure, there is provided a method performed by a network side device for receiving a transmission on a RACH from a communication device, the method comprising: receiving, by a network side device, a mobile station radio access capability (MS RAC) message from a communication device; sending, by a network side device, a network assigned Identification (ID) after receiving the MS RAC, the ID being locally unique and providing contention resolution; and receiving other transmissions on the RACH by the communication equipment by the network side equipment through the communication equipment by using the ID and the timing advance TA determined by the communication equipment.

According to another aspect of the present disclosure, there is provided a network side device receiving a transmission on a RACH from a communication device for performing the aforementioned method.

Drawings

Fig. 1 illustrates a base station and a mobile station of a wireless network in accordance with some embodiments;

figure 2 shows the timing of access burst transmission by a mobile station when the timing advance is unknown;

fig. 3 illustrates a conventional access burst structure;

FIG. 4 illustrates a functional block diagram of a mobile station in accordance with some embodiments; and

fig. 5 illustrates a process for fast contention resolution according to some embodiments.

Fig. 6 illustrates a process for registration using fast contention resolution according to some embodiments.

Fig. 7 illustrates a procedure for zero contention resolution with fixed RACH allocation, in accordance with some embodiments.

Fig. 8 illustrates a fixed RACH allocation frame structure in accordance with some embodiments.

Fig. 9 illustrates a procedure for zero contention resolution with flexible RACH allocation, in accordance with some embodiments.

Fig. 10 illustrates a flexible RACH allocation frame structure in accordance with some embodiments.

Detailed Description

The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of others. Embodiments set forth in the claims encompass all available equivalents of those claims.

Fig. 1 illustrates a wireless network in accordance with some embodiments. Wireless network 100 includes a Base Station (BS)104 and one or more mobile stations or other communication devices 102. In some embodiments, wireless network 100 may be a GSM network, including a GPRS or EGPRS network, but this is not required. According to some embodiments, a communication device such as the mobile station 102 may be configured to transmit small amounts of data (e.g., Machine Type Communication (MTC)) infrequently on the RACH 105. When the Timing Advance (TA) is known to the mobile station 102, the mobile station 102 may perform initial access on the RACH 105. In these embodiments, the initial access may comprise transmitting an initial access burst 103, the initial access burst 103 comprising at least one of an identifier and user data that may be used to identify the mobile station 102. The user data is data other than control data and other information conventionally included on the RACH. The user data has a network destination (i.e., other than the base station or base station controller). In some embodiments, the identifier may be a shortened identifier.

The timing advance may be an amount of time (or an estimate thereof) by which the mobile station 102 may advance the transmission of its initial access burst 103 such that the initial access burst 103 is received by the base station 104 in a single time slot of the RACH105 (i.e., not across more than one time slot that would result if the timing advance were unknown). The timing advance depends on the signal propagation delay between the mobile station 102 and the base station 104. The timing advance may be a timing advance associated with the serving cell. In some embodiments, a timing advance may be applied to any transmission burst that needs to be received in a time period (e.g., a time slot) of a time division multiplexed uplink channel.

In some embodiments, the parameters defining RACH105 transmitted in notification 101 may include an indication of a time slot of a physical channel including RACH105, and the like. In these embodiments, the mobile station may transmit the initial access burst 103 to include the shortened identifier. The shortened identifier may be used to identify the mobile station 102. These embodiments are discussed in more detail below.

Since the RACH105 is a random access channel in which the mobile station 102 is not allocated a specific channel resource on which to transmit the initial access burst 103, collision may occur. Embodiments discussed in more detail below may reduce or eliminate the probability of such collisions.

On the RACH105, the data transmitted in the initial access burst 103 may have a network destination within the communication network 100, rather than being used by the base station 104. Using the RACH105 for transmitting smaller amounts of data (as in MTC) can result in a significant reduction in the amount of network resources traditionally used to transmit data. In these embodiments, the signaling conventionally required for channel resource requests may be reduced or eliminated, and the establishment of a Temporary Block Flow (TBF) may not be required. In some embodiments, discussed in more detail below, signaling and network resources associated with the acknowledgement may also be reduced or eliminated.

The RACH105 is simply an uplink channel in which access is contention based and may not require a known timing advance. In the case where contention-based access is used, the mobile station 102 may autonomously select when to transmit on the RACH105 and there may be no device-specific scheduling. Access on the RACH105 may assume that the timing advance is unknown. Contention-based access on the RACH105 allows the mobile station 102 to trigger a request for uplink resources based on the requirements (rather than scheduling periodic uplink resources, for example, which may not be needed). In the case where contention-based access is used, there may be a risk that two or more mobile stations 102 will transmit overlapping access bursts.

Fig. 2 shows transmissions by a mobile station when the timing advance is unknown. After one-way signal propagation delay 211, mobile station 102 may receive transmission 202 from base station 104. Since mobile station 102 can synchronize its timing 203 (observed timing) with the transmission received by base station 104, transmission 202 can be received at mobile station 102 within a single time slot. On the other hand, a transmission 204 from the mobile station 102 to the base station 104 may be received at the base station 104 in more than one time slot 205 because the mobile station 102 does not know the timing advance value. Thus, during the conventional initial access phase, the mobile station 102 may transmit an access request message using a conventional access burst with additional guard bits (fig. 1) to mitigate unknown propagation delays at the mobile station 102. As a result, due to the long guard period, conventional access bursts on the RACH105 may be limited in the amount of useful information that may be included therein. In GSM and EDGE networks, the useful amount of information can be limited to 8 or 11 bits.

The transmission 202 may be a normal burst transmission from the base station 104 and may be used by the mobile station 102 to synchronize its timing 203, but this is not required. The mobile station 102 may use other base station transmissions, such as a synchronous transmission from the network, to synchronize its timing 203.

After an initial access procedure, which may be part of an initial timing advance estimation procedure, the network may determine and assign a timing advance value to the mobile station 102 so that subsequent communications on the control and data channels are received in designated time slots. In this way, a normal burst can be used and the use of a large number of guard bits can be avoided. The network may also regularly update the timing advance value based on a timing change (variance) of an access burst transmitted on the uplink control channel. In the case of GPRS and EGPRS configured networks, the timing advance may be updated based on the timing change of the access burst transmitted on the uplink PTCCH using a packet timing advance control channel (PTCCH). This is a continuous timing advance update procedure, which may require additional signaling. The network may also monitor the delay of normal bursts and access bursts transmitted by the mobile station 102 on various control channels (in the case of explicit polling for access bursts, for example, by the network).

Fig. 3 shows a conventional access burst structure. An access burst according to the burst structure 320 may be used to request and establish a packet data connection using the RACH channel 105. The burst structure 320 may be used for initial access by using the RACH channel 105 to transmit an access request message when the timing advance is not known by the mobile station. The synchronization sequence field 322 is the same for all mobile stations 102 and may be used by the network to evaluate the distance of the mobile stations. Depending on the coding scheme used, the data field 324 may contain a predetermined number (e.g., 8 or 11) of information bits, and the guard time field 326 may be used to help ensure that the data field 324 is correctly received by the base station 104 within the time slot. The burst structure 320 may also include tail bits 328. In GPRS and EGPRS wireless networks, a mobile station 102 may request resources by sending an access request message, which may be referred to as a channel request message or an EGPRS packet channel request message, on a RACH channel 105.

The access request message sent on the RACH channel 105 may include information for establishing a subsequent connection in the data field 324 (rather than user data having a network destination). For example, the data field 324 may include: a cause, a request for one or two phase access, and/or a random reference is established. Since data field 324 is part of the access request message, data field 324 does not include user data having a network destination. The user data is data other than control data and other information conventionally included on the RACH. The user data has a network destination (i.e., other than the base station or base station controller). The data field 324 may include data that is used only by the base station 104 or a network controller, such as a base station controller (not shown in fig. 1), for allocating resources (e.g., time slots, carriers, spreading codes, etc.) for subsequent transmission of data that may have a network destination.

The legacy access request message may be retransmitted (e.g., in the event that no response is received from the network) up to a maximum number, which may be indicated by the network in the RACH control parameter information element. The interval between successive attempts may be configured to reduce or minimize collisions with other mobile stations. After sending the access request message, mobile station 102 may listen to the broadcast channel (BCCH) and downlink common control channel slots for an immediate allocation message from the network for allocating network resources. The network may also send an immediate allocation reject message when no resources are available.

Fig. 4 illustrates a functional block diagram of a mobile station in accordance with some embodiments. Mobile station 400 may include transceiver circuitry 404 and processing circuitry 406. The transceiver circuitry 404 may be coupled to one or more antennas 408 for transmitting and receiving signals from base stations, such as the base station 104 (fig. 1). Mobile station 400 may be suitable for use as any mobile station 102 (fig. 1) as well as base station 104.

According to some embodiments, the mobile station 400 may be configured to transmit data on a random access channel. In these embodiments, the processing circuitry 406 may configure an initial access burst, such as the initial access burst 103 (fig. 1), for transmission on a RACH, such as the RACH105 (fig. 1). The initial access burst may include at least one of a shortened identifier and data having a network destination and may be configured to be no larger than a single time slot of the RACH 105. When the timing advance is known, the transceiver circuitry 404 may transmit an initial access burst 103 with a timing advance, such as timing advance 209 (fig. 2), to be received in a single time slot of the RACH.

In some embodiments, the shortened identifier, which may be included in the initial access burst 103 on the RACH105, may be determined by the mobile station 102 or the base station 104 based on a full length (e.g., 32-bit) identifier that uniquely identifies the mobile station 102. In these embodiments, the shortened identifier may be based on a 32-bit International Mobile Subscriber Identity (IMSI), a Temporary Logical Link Identifier (TLLI), a Temporary Mobile Subscriber Identity (TMSI), or some other identifier of the mobile station 102. For example, the shortened identifier may include the last 5 bits of the full-length identifier. In these embodiments, the shortened identifier may be determined by either the mobile station 102 or the base station 104.

In some embodiments, the shortened identifier may be substantially shorter than the full-length IMSI or TLLI identifier. In some embodiments, the shortened identifier may be assigned by the network and may be determined based on a particular cell or cell ID. In some embodiments, a partial identifier may be used in conjunction with a RACH group (discussed below) to identify mobile stations and reduce contention resolution. In some embodiments, a hash function (i.e., a hash of the full-length identifier or the shortened identifier) may be used. In some alternative embodiments, a full length identifier may be used in the initial access burst 103 on the RACH 105.

In some embodiments, the notification 101 may include a shortened identifier in the initial access burst 103 that is used by the mobile station 102 to identify the mobile station. In these embodiments, the base station 104 may provide the shortened identifier to the mobile station 102 for use on the RACH105, but this is not required. In some embodiments, a shortened identifier may be provided in addition to or instead of providing the parameters defining RACH105 transmitted in notification 101.

In some embodiments, mobile station 400 may be part of a portable wireless communication device, such as a Personal Digital Assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a smartphone, or other device that may receive and/or transmit information wirelessly.

Antennas 408 may include one or more directional or omnidirectional antennas, including, for example: dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some embodiments, instead of two or more antennas, a single antenna with multiple apertures may be used. In these embodiments, each aperture may be considered a separate antenna. In some multiple-input multiple-output (MIMO) embodiments, the antennas 408 may be effectively separated to take advantage of spatial diversity and the different channel characteristics that result between each antenna 408 and the transmitting station's antenna.

Although mobile station 400 is shown as having several separate functional elements, one or more of the functional elements may be combined and the functional elements may be implemented by combinations of software-configured elements, such as processing elements including Digital Signal Processors (DSPs), and/or other hardware elements. For example, some units may include: one or more microprocessors, DSPs, Application Specific Integrated Circuits (ASICs), Radio Frequency Integrated Circuits (RFICs), and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements of mobile station 400 may refer to one or more processes operating on one or more processing elements.

Fig. 5 illustrates a process for fast contention resolution according to some embodiments. Process 500 may be performed by a mobile station or other device 102. Operation 510 comprises: the identifier of the MS is mapped to a locally unique identifier that provides contention resolution. In some embodiments, the MS receives the mapped identifier from the BS. In some embodiments, the mobile station has limited or fixed mobility. Operation 520 includes: the timing advance of the MS is determined based on the known propagation delay between the MS and the BS. The propagation delay may be known when there is a fixed distance between the MS and the BS. In some embodiments, the MS receives a timing advance from the BS. Knowing the timing advance may allow the MS to use additional bits in the data frame to transmit the identifier. Furthermore, in some embodiments where the mobile station may be restricted to a particular cell, the identifier may be defined only in the particular cell to allow fewer bits to be used. Operation 530 comprises transmitting a locally unique identifier of the MS in a portion of an initial transmission on the RACH. The initial transmission is a transmission that may be initiated autonomously by the MS. Although the locally unique identifier may be used preferentially over the global identifier because it uses fewer bits, in some embodiments (operation 540), the locally unique identifier may be a full length identifier, such as a Temporary Logical Link Identifier (TLLI) or a Temporary Mobile Subscriber Identity (TMSI), and/or may be a globally unique identifier, such as an International Mobile Subscriber Identity (IMSI), or some other identifier derived from any of the above.

Fig. 6 illustrates a process for registering in fast contention resolution according to an embodiment. The process 600 may be performed by a mobile station or other device 102 to register on a network for data services. The data service may include Machine Type Communication (MTC). Operation 610 includes: a mobile station radio access capability (MS RAC) message is sent to the network. The MS RAC contains session characteristic information such as the period of transmission and the size of the data samples. Operation 620 includes: an Identification (ID) is received from the network, which may be locally unique and provides contention resolution. Operation 630 includes: a timing advance is received from a network. The operations 640 include: another transmission is performed on the RACH using the ID. At operation 650, the registration process may be repeated as needed, such as resetting the MS when served by a different cell, timing advance changes, or failure during registration.

In some embodiments, the registration may be implemented between the device and the base station rather than at the network level.

Fig. 7 illustrates a procedure for zero contention resolution with fixed RACH allocation, in accordance with some embodiments. The process 700 may be performed by a mobile station or other device 102. Operation 710 includes: the mobile station accepts the assignment of the dedicated RACH for further transmission. In some embodiments, the time instances at which the MS is allowed to transmit on the RACH maySubstantially aligned with the time at which the mobile station is required to monitor the paging channel. This synchronization may result in the MS reducing power consumption. In operation 720, the mobile station accepts membership for a RACH group. Members of a RACH group may be assigned to transmit on a frame on the RACH dedicated to that group. At operation 730, the mobile station receives a combination of the ID and RACH group that can uniquely identify a device within a cell or within a cluster of cells or within a network, providing contention resolution. In operation 740, the mobile station receives a global identifier of the device, which may be determined from a combination of the ID and the RACH group. In some embodiments, the global identifier may be: a Temporary Logical Link Identifier (TLLI), an International Mobile Subscriber Identity (IMSI), or a Temporary Mobile Subscriber Identity (TMSI). In operation 750, a group frame number is calculated based on the ID and the fixed repetition period. In some embodiments, the fixed repetition period may be an integer multiple of 51. In some embodiments, the RACH group has a maximum of 2^∧(n-1) membership, where n is the number of bits in the random number reference of the access burst.

In some embodiments, the mobile station may autonomously determine the RACH group and/or ID. For example, the RACH group and ID may be IMSI based and the MS may not be required to receive the RACH group and ID from the network.

Fig. 8 illustrates a fixed RACH allocation frame structure in accordance with some embodiments. The top row 810 specifies the device RACH group by letter. The bottom row 820 specifies sequentially increasing frame numbers. As shown, in some embodiments, the RACH group may be repeated periodically, as shown at 830, the fixed repetition period may be an integer multiple of 51.

In some embodiments, the device may be the only member in the RACH group that enables the network to identify the device based only on membership in the RACH group.

In some embodiments, if the device is unable to access the network after a certain number of attempts, the device may fall back to repeat the registration using the conventional RACH network access procedure.

Fig. 9 illustrates a procedure for zero contention resolution with flexible RACH allocation, in accordance with some embodiments. Process 900 may be performed by a mobile station or other device 102. The process is similar to that shown in fig. 7, except that the repetition period is variable and may be advantageous for devices with non-periodic access or data transmission requirements. At operation 910, a variable repetition period may be calculated according to the transmission frequency requirements of the members of the RACH group. Further, at operation 920, a unique offset of the group frame number may be calculated from the RACH group. In operation 930, a group frame number is calculated based on the ID, the variable repetition period, and the unique offset.

Fig. 10 illustrates a flexible RACH allocation frame structure in accordance with some embodiments. The top row 1010 specifies the device RACH group by letter. The bottom row 1020 specifies sequentially increasing frame numbers. The RACH group frame number is calculated based on its period and offset, and an example is shown at 1030. For example, RACH group a has a periodicity of 4 and an offset of 0, and thus uses

frames

0, 4, 8, and so on. Similarly, RACH group B has a periodicity of 8 and an offset of 1, and thus uses

frames

1, 9, 17, and so on.

Although the individual operations of

procedures

500, 600, 700, and 900 are illustrated and described as separate operations, one or more of the individual operations may be performed concurrently, and nothing requires that the operations be performed in the order illustrated. Further, the same operation may be optional.

Embodiments may be implemented in one or a combination of hardware, firmware, and software. Embodiments may also be implemented as instructions stored on a computer-readable storage medium, which may be read and executed by at least one processor to perform the operations described herein. Computer-readable media may include any tangible medium for storage in a form readable by a machine (e.g., a computer). For example, a machine-readable medium may include: read Only Memory (ROM), Random Access Memory (RAM), magnetic disk storage media, optical storage media, and flash memory devices.

Although many of the embodiments described herein relate to GSM networks including GPRS and EGPRS, the embodiments are generally applicable to any wireless network that uses TDMA random access channels.

The abstract of the specification is provided to comply with 37 c.f.r Section 1.72(b), which requirement abstract of the specification will allow the reader to ascertain the nature and gist of the technical disclosure. The applicant believes that it should be understood that: it is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. Thus the following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Claims

1. A method performed by a network side device for receiving a transmission on a random access channel, RACH, from a communication device, the method comprising:

receiving a mobile station radio access capability MS RAC message from the communication equipment by the network side equipment;

after receiving the MS RAC, sending, by a network side device, a network assigned identification ID, which is locally unique and provides contention resolution;

and receiving, by the network side device, user data on the RACH from the communication device using the ID and the timing advance TA determined by the communication device.

2. The method of claim 1, wherein the receiving of the MS RAC message is performed by a base station, BS, serving a cell, and the transmitting is from the BS to the communication device.

3. The method of claim 1, wherein the method is performed for registration on a network and is repeated when:

providing, by a different cell, a service to the communication device;

resetting the communication device;

the registration fails; or

The timing advance has changed.

4. The method of claim 3, wherein the registration is for a data service.

5. The method of claim 1, further comprising: transmitting, by a network side device, an assignment for a RACH dedicated to the communication device for the user data.

6. The method of claim 2, further comprising: transmitting, by a network side device, an assignment message for membership of a RACH group, wherein a member assigned to the RACH group is transmitted on a frame on the RACH, the frame being dedicated to the RACH group.

7. The method of claim 6, further comprising: transmitting, by a network side device, a combination of the ID and the RACH group, the combination uniquely identifying the communication device in the cell and providing contention resolution.

8. The method of claim 7, further comprising: sending, by a network side device, a global identifier of the communication device, wherein the global identifier is determined from the combination.

9. The method of claim 8, wherein the global identifier comprises: the international mobile subscriber identity IMSI.

10. The method of claim 6, further comprising: calculating a group frame number from the ID and from a fixed repetition period.

11. The method of claim 6, wherein the RACH group has a maximum of 2^ (n-1) membership, where n is the number of bits in the random number reference in an access burst.

12. The method of claim 6, further comprising: calculating a group frame number from the ID and from a variable repetition period.

13. The method of claim 12, wherein the variable repetition period depends on transmission frequency requirements of members of the RACH group.

14. The method of claim 6, wherein a group frame number is calculated such that a unique offset is applied according to the RACH group.

15. A network side device receiving a transmission on a random access channel, RACH, from a communication device for performing the method according to any of the preceding claims.